Performed hydraulic evaluations to identify system
deficiencies and recommended improvements, and developed an
optimized capital improvement program, identifying costs and time
line for implementation

Evaluated the water system under both average and peak demand
conditions

West Yost prepared EMWD’s 2015 Water Facilities Master Plan
(WFMP) Update for its potable water system. Key drivers for the
WFMP included significant changes in growth projections since the
previous WFMP, and EMWD’s need to update its capital improvement
program (CIP) for re-evaluation of rate and connection fees.

West Yost worked collaboratively with EMWD to provide key input
to the District’s future water supply strategy. Using a
skeletonized version of the distribution system hydraulic model
that includes key backbone transmission facilities, West Yost
identified transmission needs for different water supply
alternatives to support EMWD decision-making for its water supply
strategy. West Yost also used the backbone model to identify
phasing of facilities, to determine sequencing of supplies to
serve Perris Valley, EMWD’s largest pressure zone, and to
evaluate facilities needs for outage planning.

West Yost prepared a comprehensive analysis of all EMWD pressure
zones, to determine supply, storage and pipeline capacity needs
for each pressure zone. Hydraulic modeling for the system used
extended period simulations, using seven successive maximum
demand days to confirm operational trends. West Yost used the
buildout scenario to establish facilities requirements, and then
performed hydraulic evaluations for a number of different time
frames (2016, 2018, 2020, 2022, 2025, 2030, 2035, 2040 and 2045)
to establish facilities phasing. Average day scenarios were also
evaluated for 2025 and buildout to assess pressures under lower
demand conditions.

The analysis found that there were varying needs to provide
improvements, depending on service area, growth and water
supplies, with an overall CIP of $1.9 billion. West Yost
prioritized improvements to address existing deficiencies first.
Remaining improvements were generally tied with growth and timing
of the improvements was based on the timing of development.
Projects that benefit specific developments were also identified,
so that funding for improvements could be allocated to the
specific development.

Improvement projects were developed and tested through an
iterative and collaborative process. After initial solutions were
developed, these were reviewed with EMWD’s internal stakeholder
group. Based on input received, alternative solutions were tested
and/or improvements were refined to incorporate EMWD suggestions.